Fixed: Changes in http redirect logic causing failed grabs and >25% cpu usage.

src/NzbDrone.Common.Test/Http/HttpClientFixture.cs

@@ -139,11 +139,26 @@ namespace NzbDrone.Common.Test.Http
             var request = new HttpRequest($"http://{_httpBinHost}/redirect/1");
             request.AllowAutoRedirect = true;
 
-            Subject.Get(request);
+            var response = Subject.Get(request);
+
+            response.StatusCode.Should().Be(HttpStatusCode.OK);
 
             ExceptionVerification.ExpectedErrors(0);
         }
 
+        [Test]
+        public void should_not_follow_redirects()
+        {
+            var request = new HttpRequest($"http://{_httpBinHost}/redirect/1");
+            request.AllowAutoRedirect = false;
+
+            var response = Subject.Get(request);
+
+            response.StatusCode.Should().Be(HttpStatusCode.Found);
+
+            ExceptionVerification.ExpectedErrors(1);
+        }
+
         [Test]
         public void should_follow_redirects_to_https()
         {

src/NzbDrone.Common/Http/HttpClient.cs

@@ -52,36 +52,33 @@ namespace NzbDrone.Common.Http
 
         public HttpResponse Execute(HttpRequest request)
         {
-            var autoRedirectCount = 0;
+            var response = ExecuteRequest(request);
+
+            if (request.AllowAutoRedirect && response.HasHttpRedirect)
+            {
                 var autoRedirectChain = new List<string>();
                 autoRedirectChain.Add(request.Url.ToString());
 
-            var response = ExecuteRequest(request);
-
-            while (response.StatusCode == HttpStatusCode.Moved ||
-                   response.StatusCode == HttpStatusCode.MovedPermanently ||
-                   response.StatusCode == HttpStatusCode.Found)
-            {
-                if (request.AllowAutoRedirect)
+                do
                 {
                     request.Url += new HttpUri(response.Headers.GetSingleValue("Location"));
                     autoRedirectChain.Add(request.Url.ToString());
 
                     _logger.Trace("Redirected to {0}", request.Url);
 
-                    autoRedirectCount++;
-                    if (autoRedirectCount > 3)
+                    if (autoRedirectChain.Count > 3)
                     {
                         throw new WebException($"Too many automatic redirections were attempted for {autoRedirectChain.Join(" -> ")}", WebExceptionStatus.ProtocolError);
                     }
 
                     response = ExecuteRequest(request);
                 }
-                else if (!RuntimeInfo.IsProduction)
-                {
-                    _logger.Error("Server requested a redirect to [{0}]. Update the request URL to avoid this redirect.", response.Headers["Location"]);
-                    break;
+                while (response.HasHttpRedirect);
             }
+
+            if (response.HasHttpRedirect && !RuntimeInfo.IsProduction)
+            {
+                _logger.Error("Server requested a redirect to [{0}] while in developer mode. Update the request URL to avoid this redirect.", response.Headers["Location"]);
             }
 
             if (!request.SuppressHttpError && response.HasHttpError)

src/NzbDrone.Common/Http/HttpResponse.cs

@@ -51,6 +51,10 @@ namespace NzbDrone.Common.Http
 
         public bool HasHttpError => (int)StatusCode >= 400;
 
+        public bool HasHttpRedirect => StatusCode == HttpStatusCode.Moved ||
+                                       StatusCode == HttpStatusCode.MovedPermanently ||
+                                       StatusCode == HttpStatusCode.Found;
+
         public Dictionary<string, string> GetCookies()
         {
             var result = new Dictionary<string, string>();